Influences Of Different Mulches On Soil Moisture,Heat And Winter Wheat Growth

In arid and semi-arid region of northwest China which lacks of precipitation,mulches can modulate soil temperature,increase soil water content and improve the water use efficiency,so as to increase crop production.At the same time,mulches also increase soil surface resistance,which benefits to reducing wind erosion and wind erosion.In this paper,an outdoor rain-sheltering experiment was conducted to explore the influences of winter wheat under different mulches(straw-mulches with lengths of 1mm(S1),10mm(S10),50 mm(s50)and 100mm(S100),white film mulching(WF),black film mulching(BF),WF+S1(WS),BF+S1(BS)and gravel-sand mulching(GS))in institute of water-saving agriculture in arid area of China from Oct,2015 to May,2016.Basing on the measured data collected from small lysimeter,this study compares to single and dual crop coefficient methods to calculate the evapotranspiration of winter wheat.Using HYDRUS-1D modeling,we simulated the soil moisture of winter wheat under different mulches.The results are as follows:(1)The dynamics of soil moisture and temperature of winter wheat were affected by different mulches significantly: overall,straw mulching treatment is better than film mulching treatment to keep soil moisture,and sand-gravel treatment is in the middle.The water retention capacity is closely related to the straw lengths between 1-10 centimeters,the longer length of straw,the better effect of keeping soil water content.Black film mulching series are better than white film mulching series to reduce soil evaporation,and the plastic film mulching with straw is better than single plastic film mulching,too.Compared with controls,all covering measures suppressed the soil evaporation and improved the soil moisture content in different degrees.Straw mulching and gravel sand mulching treatments have the dual roles of warming and cooling from the whole growth period,and overall film mulching plays the role of warming.Black film mulching series have better effect of increasing soil temperature than white film mulching series,and the film mulching with straw is better than single plastic film mulching,too.(2)Generally,all covering treatments extended winter wheat growth stages,and the longer length of straw,the better effect of delaying growth period.The growth period of black film mulching is slightly longer than the white film mulching,and so it is with the film mulching with straw and single plastic film mulching.(3)All covering treatments significantly increased the winter wheat plant height and leaf area index.Winter wheat plant height of the film mulching and sand gravel mulching is taller than straw mulching,and so it is with white film mulching and black film mulching.And straw mulching with different lengths showed no obvious changes.The leaf area index of straw mulching is greater than the plastic film mulching and sand gravel mulching,especially the lengths of 5 and 10 centimeters,which is significantly greater than other treatments.The leaf area index and plant height of winter wheat can be simulated by Logistic curves,building the regression formulas under different mulches.All the processes of winter wheat growth fitted well with S-shape curves.(4)All covering treatments increased the number of winter wheat spikes and thus effectively improved the yield,but it showed no obvious changes on 1000-grain weight and the spike length.And all covering treatments also increased the WUE of winter wheat,and the longer length of straw,the better effect of the WUE.The WUE of black film mulching is bigger than white film mulching,and gravel sand mulching is in the middle.(5)The calculated values based on single or dual crop coefficient method is less than the measured values in general.The fitting effect is better after correction,and the fitting effect of dual crop coefficient method is obviously better than the single crop coefficient method.Compared with no covering treatment,the fitting effect of covering treatments is better and the longer length of the straw,the better fitting effect.(6)HYDRUS-1D modeling has good simulating effect on winter wheat soil moisture under different mulches,which fairly reflects the dynamics of soil water content during the whole growth period.Therefore,HYDRUS modeling still has feasibility on winter wheat under plastic film mulching and gravel sand mulching conditions.